Right off hand:
Iowa State Patrol, M&P40
New Mexico State Police, M&P357
Rocky Mount, NC PD, M&P40 (I think)
North Carolina Department of Corrections, Prisons and Probation/Parole, M&P40
New Hampshire State Police, M&P45
Patrick County, VA SO, M&P40
I'm sure there are others. Some of the agencies above might be in the transition process to the M&P, but the decision has been made.